367 research outputs found

    The relationship between volatile content and the eruptive style of basaltic magma: the Etna case

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    Fourier Transform Infrared (FT-IR) spectroscopic analyses of melt inclusions from four explosive eruptions of Etna (Italy) were conducted to determine pre-eruptive dissolved volatile concentrations. The studied eruptions include the 3930 BP subplinian, the 122 B.C. plinian, and the 4 January 1990 and the 23 December 1995 fountain fire eruptions. Preliminary results indicate that H2O varies between 3.13 and 1.02 wt% and CO2 between 1404 and 200 ppm. The most basic products (3930 BP tephra) contain the highest concentrations of CO2 (1404 ppm), whereas fire fountain hawaiitic tephra present the lowest values (< 200 ppm) indicating a continuous degassing process during the differentiation and rising of the magma. Generally, similar behavior has been found for water, characterized by a decreasing content during the differentiation that is mainly found in the 3930 BP eruption, 1990 and 1995 fire fountain products. Considering the relevance of volatile content and behaviour in determining the eruptive style, we made some inferences on the eruptive mechanisms based on the initial high volatile content and the degassing dynamics inside the plumbing system. These two factors suggest the cause of the high explosive activity in this basaltic volcano

    Late Pleistocene-Holocene volcanic activity in northern Victoria Land recorded in Ross Sea (Antarctica) marine sediments

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    Eight pyroclastic fall deposits have been identified in cores of Late Pleistocene-Holocene marine sediments from the Ross Sea (Antarctica), and their components, granulometry and clast morphologies were analysed. Sedimentological, petrographic and geochemical analysis of clasts, with 40Ar-39Ar dating of alkali feldspar grains, indicate that during this period at least five explosive eruptions of mid to high intensity (plinian to subplinian) occurred, and that three of these eruptions took place from Mount Melbourne volcanic complex, between 137.1 \ub1 3.4 and 12 ka. Geochemical comparison of the studied tephra with micro and crypto-tephra recovered from deep Antarctic ice cores and from nearby englacial tephra at Frontier Mountain indicates that eruptive activity in the Melbourne Volcanic Province of northern Victoria Land was intense during the Late Pleistocene-Holocene, but only a general area of provenance for the majority of the identified tephra can be identified

    Magma dynamics during the 2007 Stromboli eruption (Aeolian Islands. Italy): mineralogical, geochemical and isotopic data

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    After the 6 month-long effusive event of 2002-2003, a new lava effusion occurred at Stromboli between 27 February and 2 April 2007. Despite the different durations, approximately the same volume of magma was emitted in both eruptions, in the order of 107 m3 . A paroxysmal eruption occurred at the summit craters in both the 2002–2003 and 2007 episodes, during which a significant amount of low porphyritic (LP), volatile- rich magma was erupted. In both cases, the paroxysm did not interrupt the lava emission. Here, we present compositional data, including texture, mineralogy, chemistry and Sr and Nd isotope ratios of bulk-rock, groundmass and separated minerals of lavas erupted in 2007, together with chemistry and Sr and Nd isotope composition of the pumices emitted during the 15 March paroxysm. As a whole, the lavas have the same texture and chemistry that characterize the highly porphyritic (HP) products usually erupted at Stromboli during normal Strombolian activity and effusive events. Compared to the previous HP products, the 2007 lavas show minor but systematic mineralogical and isotopic variations which are consistent with a modest increase of the magma supply rate of the volcano. Compositional variations during the entire duration of the event are very modest. Glass chemistry changes in lavas erupted in the second half of March can be explained by theminormixing between the volatile-rich LPmagma rising through the shallowmagmatic systemduring the 15 March paroxysm and the degassed residing HP magma. A first conclusion of this study is that there is no compositional evidence supporting major changes in the magma dynamics of the volcano accompanying the effusive activity, as also suggested for the 2002–2003 event. The activity of Stromboli is controlled by a steady state feeding system in which refilling, mixing, degassing and crystallization at shallow level continuously operate,withmodest oscillations in themagma supply rate. Switching between normal Strombolian and effusive activity is related to periods of relatively more vigorous refilling of the shallow system, leading to progressive pressure increase in the upper conduits associated with only minor compositional variations in the erupted products

    Clinical trials for elderly patients with multiple diseases (CHROMED) pilot study

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    The problem COPD (Chronic Obstructive Pulmonary Disease) is a significant socioeconomic burden which, particularly when associated with comorbidities such as Chronic Heart Failure (CHF), markedly affects patient outcomes. Care models based on telemedicine systems that enable early diagnosis and treatment of exacerbations are advocated to reduce the impact of chronic diseases on patient outcomes and health service costs. CHROMED (www.chromed.eu) is an international EU-funded project aimed at developing a multi-centre clinical trial to evaluate the impact of a new integrated home care approach to reduce care costs and improve quality of life in COPD. The approach We collaborated in a pilot study prior to the main trial which will include 300 patients from seven European countries (Italy, Spain, UK, Estonia, Slovenia, Sweden and Norway) with nine partners. The home monitoring system includes a novel forced oscillation technique (FOT) device for self-measurement of lung mechanics (RESMONPRO DIARY, Restech srl, Italy), a touch screen for collecting patients' symptoms and, where COPD is associated with CHF, by a device for measuring heart rate (HR), blood pressure (BP), pulse oximetry (SpO2) and body temperature (WRIST CLINIC, Medic4all, Israel). Findings The pilot included 16 patients (n=11 COPD, 5 COPD+CHF). The average monitoring period was 48.3±23.4 days resulting in a total of 504 patient days. The percentage of data correctly received within the period was: lung impedance and breathing pattern 90.0%; HR 91.7%, BP 91.7%; SpO2 74.0% and body temperature 71.4%. During the pilot, one patient was treated pharmacologically for an exacerbation of COPD. Offline processing demonstrated that the system identified warning of an exacerbation five days prior to admission. We also analysed qualitative data from patients and professionals about the acceptability of the telemedicine system and the interaction between patients, professionals and the monitoring system. Consequences The data suggest good acceptability and short-term compliance among patients with COPD. Lung function, HR and BP provided the most reliable data. The full RCT is currently under way and will be completed in August 2015

    Differential role of circulating micrornas to track progression and pre-symptomatic stage of chronic heart failure: A pilot study

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    (1) Background: Chronic heart failure (CHF) contributes to the overall burden of cardiovascular disease. Early identification of at-risk individuals may facilitate the targeting of precision therapies. Plasma microRNAs are promising circulating biomarkers for their implications with cardiac pathologies. In this pilot study, we investigate the possible exploitability of circulating micro-RNAs (miRNAs) to track chronic heart failure (CHF) occurrence, and progression from NYHA class I to IV. (2) Methods: We screened 367 microRNAs using TaqMan microRNA Arrays in plasma samples from healthy controls (HC) and CHF NYHA-class I-to-IV patients (5/group). Validation was performed by singleplex assays on 10 HC and 61 CHF subjects. Differences in the expression of validated microRNAs were evaluated through analysis of covariance (ANCOVA). Associations between N-terminal pro-BNP (NT-proBNP), left ventricular end-diastolic volume (LVEDV) or peak oxygen uptake (VO2 peak) and plasma microRNA were assessed by multivariable linear regression analysis. (3) Results: Twelve microRNAs showed higher expression in CHF patients vs. HC. Seven microRNAs were associated with NT-proBNP concentration; of these, miR-423-5p was also an independent predictor of LVEDV. Moreover, miR-499-5p was a predictor of the VO2 peak. Finally, a cluster of 5 miRNAs discriminated New York Heart Association (NYHA) class-I from HC subjects. (4) Conclusions: Our data suggest that circulating miRNAs have the potential to serve as pathophysiology-based markers of HF status and progression, and as indicators of pre-symptomatic individuals

    Peptidyl-prolyl isomerases : A full cast of critical actors in cardiovascular diseases

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    Peptidyl-prolyl cis-trans-isomerases are a highly conserved family of immunophilins. The three peptidyl-prolyl cis-trans-isomerase subfamilies are cyclophilins, FK-506-binding proteins, and parvulins. Peptidyl-prolyl cis-trans-isomerases are expressed in multiple human tissues and regulate different cellular functions, e.g. calcium handling, protein folding, and gene expression. Moreover, these subfamilies have been shown to be consistently involved in several cardiac and vascular diseases including heart failure, arrhythmias, vascular stenosis, endothelial dysfunction, atherosclerosis, and hypertension. This review provides a concise description of the peptidyl-prolyl cis-trans-isomerases and presents an incisive selection of studies focused on their relationship with cardiovascular diseases

    The BeppoSAX High Energy Large Area Survey HELLAS, II: Number counts and X-ray spectral properties

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    The BeppoSAX High Energy Large Area Survey (HELLAS) has surveyed about 85 deg^2 of sky in the 5-10 keV band down to a flux of 4-5 10^-14 erg cm-2 s-1. The source surface density of 16.9+-6.4 deg2^{-2} at the survey limit corresponds to a resolved fraction of the 5-10 keV X-ray background (XRB) of the order of 20-30 %. Hardness ratios analysis indicates that the spectra of a substantial fraction of the HELLAS sources (at least one third) are harder than a alpha_E = 0.6 power law. This hardness may be due to large absorbing columns. The hardness ratio analysis also indicates that many HELLAS sources may have a spectrum more complex than a single absorbed power law. A soft component, superimposed to a strongly cut-off power law, is likely to be present in several sources.Comment: to appear in MNRA

    Petrology and Geochemistry of the AND-1B Core, ANDRILL McMurdo Ice Shelf Project, Antarctica

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    This section reports preliminary data and results on petrology and geochemistry of AND-1B corePublishedin press2.3. TTC - Laboratori di chimica e fisica delle rocceN/A or not JCRreserve
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